This application claims the priority of German Patent Document 199 09 932.4, filed Mar. 6, 1999, the disclosure(s) of which is expressly incorporated by reference herein.
The invention relates an electronic safety system, and in particular, a vehicle locking system.
In safety systems having one or more safety units for protection against unauthorized entry by way of entry elements (doors and the like), or against unauthorized use of vehicles and other objects, a control unit generates safety control commands based on its determination (using pertaining detection sensors) of whether or not an authorized authentication element is situated within its acquisition range. In so-called keyless go systems, active authentication element operation by the user is not required; rather, the user needs only bring the authentication element into the acquisition range of a detection sensor.
The authentication element in this case may consist, for example, of a chip card. For detecting an authentication element, the control unit emits query data signals into the acquisition range via the detection sensors. (The acquisition range is frequently defined by the capture range of an antenna unit of the particular detection sensor.) When an authentication element is situated within the acquisition range of one or more detection sensors, it receives the query data signal and returns an authentication response signal, from which the control unit can determine that the authentication element is situated within an acquisition range, and in which of the acquisition ranges, (that is, of which sensor(s)) and whether it is valid for the particular object. The safety control devices will then generate safety control commands for releasing or blocking one or more of the safety units as a function of the acquisition ranges within which the authorizing authentication element has been detected. Such systems are customary, for example, for use as locking systems and/or drive blocking devices in motor vehicles. A vehicle locking system of this type is described in the older German Patent Application No. 198 39 355 which is not prior art.
In modern vehicles, one problem of conventional keyless go systems of this type is that the acquisition ranges of the individual detection sensors and the capture ranges of their antenna units partially overlap (among other reasons, for avoiding undesirable dead zones). Such a motor vehicle anti-theft system with mutually overlapping acquisition ranges formed of capture ranges of different antenna units is disclosed in German Patent Document DE 195 42 441 C2. Since, on the other hand, frequently different safety control commands should be generated as a function of whether an authorizing authentication element exists only in one or only in the other acquisition range, it is desirable that these different authentication element positions can be differentiated.
Conventionally, this task can be accomplished, for example, by first querying one acquisition range concerning the presence of an authentication element and, if the result is positive, then querying the other acquisition range which partially overlaps with the former. In this manner, the control unit can decide whether or not the authentication element detected in one acquisition range, is also situated in the other acquisition range, and thus in the overlapping range.
However, such sequential querying of several acquisition ranges concerning an authentication element which may be situated there is relatively time consuming and may, in unfavorable cases, lead to undesirable delays in the implementation of safety function desired by the user. In addition, such multiple sequential query of different detection sensors results in separate responses to each of these sensors by the addressed authentication element. Since the query by the detection sensors usually takes place several times, a conventional authentication element searching operation includes a relatively large number of authentication response signals sent by the authentication element. The process therefore causes a corresponding energy consumption in the authentication element, and, for example, shortens the useful life of its battery.
One object of the invention is to provide an electronic safety system of the initially mentioned type (for example, in the form of a keyless go system), which accomplishes a relatively rapid determination of the various acquisition range or ranges within which an authentication element may be situated.
This and other objects and advantages are accomplished by the electronic safety system according to the invention, in which the query data signals emitted by the detection sensors characteristically contain a data protocol field coded with sensor-specific identification information (hereinafter, xe2x80x9csensor-specifically codedxe2x80x9d), that, clearly identifies the emitting detection sensor and differentiates it from the others. The respective authentication elements have devices for analyzing the sensor-specifically coded data protocol fields of received query data signals, and generate and send back an authentication response signal which contains a sensor-indicative data protocol field containing information identifying detection sensor or sensors from which a query data signal has been received.
The safety system according to the invention thus permits a comparatively short searching operation by the control unit for an authentication element present in one of the acquisition ranges. In addition, it also keeps the energy consumption in the respective authentication element relatively low, because in a searching operation the safety devices emit query data signals by way of the detection signals, which query data signals carry information in the sensor-specifically coded data protocol field indicating from which detection sensor they originate. An authentication element situated within the acquisition ranges of one or more detection sensors receives the query data signals of those detection sensors. By means of its corresponding analyzing devices, the authentication element can extract from the received query data signals information concerning identity of the sending detection sensor. The authentication element then incorporates all information indicating the detection sensors from which it has received query data signals into the authentication response signal to be sent. From this single authentication response signal, the control unit receives (in addition to possible other information), sufficient information, which it can analyze indicating from which detection sensors the authentication element could receive query data signals. That is, it can determine the different partially mutually overlapping acquisition range(s) within which the authentication element is situated.
Since the length of the sensor-specifically coded data protocol field to be incorporated into the query data signals can be kept significantly shorter than the residual length of the query data signals which comprise particularly the actual protocol part for checking the authentication, the authentication element searching operation can be kept correspondingly shorter in comparison to conventional systems with the serial query of the various acquisition ranges. In addition, the energy consumption in the authentication element for generating a single authentication response signal per searching operation according to the invention is lower than in cases in which the authentication element, if it is situated in an overlapping range of several acquisition ranges, must in each case emit a separate authentication response signal to the serial queries of the detection sensors of these acquisition ranges.
In one embodiment of the invention, the sensor-specific code information consists of an identification data block which, for the different detection sensors, is situated at different points within the sensor-specifically coded data protocol field, and is therefore suitable for the clear identification of the sending detection sensor in a simple manner.
In another embodiment, the different identification data blocks are situated without any overlapping at mutually separated points within the sensor-specifically coded data protocol field the query data signals. The sensor-indicative data protocol field of the authentication response signal is then built up in real time from the identification block data of the received query data signal (s). That is, corresponding sensor-identifying data blocks are built up at that point within the sensor-indicative data protocol field at which the pertaining identification data block was situated in the sensor-specifically coded data protocol field. Since the identification data blocks are situated at mutually separated points, they can still be identified individually in the sensor-indicative data protocol field in which the authentication element is situated in an overlapping range of several acquisition ranges, and therefore several identification data blocks are in a time-corresponding manner built into the sensor-indicative data protocol field of the authentication response signal. As the result of this relatively simple structure of the sensor-specifically coded data protocol field of the query data signals of different detection sensors as well as the sensor-specifically coded data protocol field of the authentication response signal, the implementation expenditures can be kept relatively low.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.